As much as 15 inches of rain could fall in the next 16 days in Northern California, with about 2 feet of snow expected in the highest points of the Sierra Nevada.

California's water deficit remains so profound that a "steady parade of storms" like these will be needed for years to come to end the relentless drought, said Mike Anderson, climatologist for the state's Department of Water Resources.

"We're at least on a good trajectory," he said. "We've got to keep it going."

Water managers won't be able to fully estimate this year's snowmelt until April 1, when the snowpack is typically at its deepest.

El Nino storms in the early 1980s and late 1990s brought about twice as much rain as normal, while also causing mudslides, flooding and dangerously high surf, Jet Propulsion Laboratory climatologist Bill Patzert said.